Normally, during the coating of foodstuffs with particulate material, large amounts of coating material fall off the foodstuff during the coating process, and it is important that this excess coating material is reused. In conventional equipment used, for example, in coating frozen fish on both sides with bread crumbs, excess coating material is normally transported upwards for reuse by means of elevator screws. However, not only are delicate crumbs damaged by screws, but also large amounts of coating material are always in circulation and exposed to the warm air of the environment which is not desirable since it is important that the coating material should be maintained at as low a temperature as possible. Therefore, in many cases even today, coating of certain products with particulate material is carried out manually.
In U.S. Pat. No. 4,762,083, a completely new principle is described for coating a foodstuff with a particulate material using an apparatus which is not only very much simpler but also enables very much smaller amounts of coating material to be in circulation at any period in time when compared with conventional apparatus. This apparatus comprises:
a drum capable of rotating about a substantially horizontal longitudinal axis;
a first horizontal conveyor adapted to travel through the drum;
a second horizontal conveyor below the first conveyor, adapted to travel in a direction opposite the first conveyor, the second conveyor comprising at least first, second and third successive endless belts each having a horizontal upper run and a gap between each successive pair of belts, the second belt having an inclined portion extending to a position below the first belt, the gap between the second and third belts being situated within the drum;
means for feeding particulate material onto the first conveyor; and
means for feeding a foodstuff onto the first belt;
such that in operation, particulate material is fed from the first conveyor onto the foodstuff on the first belt for coating the foodstuff on an upper side, the coated foodstuff is transported to the second belt with excess particulate material falling off the first belt onto the inclined portion of the second belt and is conveyed to the horizontal upper run of the second belt for coating the foodstuff on a bottom side, the coated foodstuff is fed to the third belt with further particulate material falling through the gap between the second and third belts onto an inside wall of the drum which rotates for conveying the further material to a position above the first conveyor upon which the further material falls by gravity, and the first conveyor transports the further material back to the second conveyor.
However, although this apparatus enables the foodstuff to be coated on all sides, the coating is not always satisfactorily uniform owing to the fact that an even distribution of particulate material is not always obtained before the particulate material reaches the foodstuff. I have now discovered that one reason for this is that the further particulate material falling through the gap between the second and third belts onto the inside wall of the drum does not form a sufficiently even layer over the whole axial width of the inside wall of the drum so that when this further particulate material has been conveyed by the rotation of the drum to a position above the first conveyor, it does not form an even layer on the first conveyor as it falls onto it. This means that the further particulate material is not transported evenly to the second conveyor on which the foodstuff is lying.